EP 0 908 569 B1 teaches a generic sieve device inserted in a shaft. The wastewater is supplied to the sieve device via a supply device consisting of a supply pipe and a loading container. The wastewater is freed from the material to be separated in the sieve device in that the water passes through the openings of a sieve surface of the sieve device and the material to be separated is transported with a worm conveyor out of the shaft into a container. In order to separate the wastewater from the material to be separated, the worm conveyor brushes along the wall of the sieve surface of the sieve device.
The edges of the worm conveyor are frequently provided with brushes in order to obtain a close contact with the sieve surface. These brushes must be cleaned regularly in order to obtain the desired separation between water and material to be separated. For this, it is necessary in the state of the art that maintenance personnel climb into the shaft, remove the sieve surfaces and clean the worm conveyor, in particular its brushes. To this end, the water is pumped out of the shaft in advance and the maintenance personnel is subsequently lowered into the shaft. This maintenance work is very unpleasant, in particular in the case of very large sieve devices that can have a length of up to 12 m. It is even forbidden in some countries for maintenance personnel to climb down into the shaft since there can be a significant danger of poisoning on account of the gases in the shaft.